using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class IKControl : MonoBehaviour {

    Animator _animator;

    public float transitionTime = 0.3f;

    public Transform lookAtDestination;
    public Transform rightHandDestination;
    public Transform leftHandDestination;
    public Transform rightFootDestination;
    public Transform leftFootDestination;

    Vector3 lookAtPoint;
    Vector3 rightHandPoint;
    Vector3 leftHandPoint;
    Vector3 rightFootPoint;
    Vector3 leftFootPoint;

    Quaternion rightHandRotation;
    Quaternion leftHandRotation;
    Quaternion rightFootRotation;
    Quaternion leftFootRotation;

    float _lookAtWeight;
    float _rightHandWeight;
    float _leftHandWeight;
    float _rightFootWeight;
    float _leftFootWeight;

    void Awake()
    {
        _animator = GetComponent<Animator>();
    }

    void Update()
    {
        if(lookAtDestination != null) { lookAtPoint = lookAtDestination.position; }
        UpdatePositionAndRotation(ref rightHandPoint, ref rightHandRotation, rightHandDestination);
        UpdatePositionAndRotation(ref leftHandPoint, ref leftHandRotation, leftHandDestination);
        UpdatePositionAndRotation(ref rightFootPoint, ref rightFootRotation, rightFootDestination);
        UpdatePositionAndRotation(ref leftFootPoint, ref leftFootRotation, leftFootDestination);

        UpdateWeight(ref _lookAtWeight, lookAtDestination);
        UpdateWeight(ref _rightHandWeight, rightHandDestination);
        UpdateWeight(ref _leftHandWeight, leftHandDestination);
        UpdateWeight(ref _rightFootWeight, rightFootDestination);
        UpdateWeight(ref _leftFootWeight, leftFootDestination);
    }

    void OnAnimatorIK(int layer)
    {
        if(lookAtDestination != null) { _animator.SetLookAtPosition(lookAtDestination.position); }
        _animator.SetLookAtWeight(_lookAtWeight);

        SetIKParams(AvatarIKGoal.RightHand, rightHandPoint, rightHandRotation, _rightHandWeight);
        SetIKParams(AvatarIKGoal.LeftHand, leftHandPoint, leftHandRotation, _leftHandWeight);
        SetIKParams(AvatarIKGoal.RightFoot, rightFootPoint, rightFootRotation, _rightFootWeight);
        SetIKParams(AvatarIKGoal.LeftFoot, leftFootPoint, leftFootRotation, _leftFootWeight);
    }

    void UpdateWeight(ref float weight, Transform destination)
    {
        weight = Mathf.Lerp(weight, destination ? 1 : 0, Time.deltaTime / transitionTime);
    }

    void UpdatePositionAndRotation(ref Vector3 position, ref Quaternion rotation, Transform destination)
    {
        if(destination != null